The DK Driver for VMS versions around 5.x definitely had a problem with non-DEC disks. 6.X and greater were slightly more forgiving.
The specifics are summarized in a note from Ralph Weber in https://groups.google.com/forum/#!search/SCSI$20Mode$20Page$20Requirements$20$20axp/comp.os.vms/RAaUpP_XXEw/BWn64YZYwBQJ . I don’t think there is list of non-DEC disks in the driver as it instead checked the SCSI Mode bits and other disk configuration settings. There is a list (table) for DEC Drives (idiosyncrasies?) and another SCSI2 Tagged Queuing devices requirements used for Clusters in the driver. Regards, Jerry > On Oct 5, 2017, at 6:23 PM, Peter Coghlan via cctalk <cctalk@classiccmp.org> > wrote: > > > >> >> The biggest problem you had was the requirement to assert ATN when selected >> properly.� Later the tag queuing caused huge headaches as manufacturers >> implemented that feature. >> >> It eventually was made mandatory for the most part by linux, and perhaps >> Windows requiring the tag queuing drilled own to the lowest level of the >> system's use of the disk. The capability to do that, or fake it is required >> to allow the kernel to queue commands to run, and have the OS continue to >> run till command completion. >> > > I recall VMS having issues with SCSI disks which claimed to do tag queueing > (and bad block replacement) but didn't do it right, before I'd even heard > of linux. > > Customers complained that VMS refused to work with commodity SCSI disks > and thought that it was a conspiracy to get them to buy expensive DEC branded > disks. DEC claimed that only the disks with their firmware did tag queueing > and bad block replacement correctly. The VMS SCSI driver supposedly had > (has?) > a list of specific disks known to mess up which it would refuse to bring > online. > > I wasn't well up on Sun but I expect the same issue existed there too. > > Regards, > Peter Coghlan.
